The purpose of a drain is to evacuate fluid or gas that is present or likely to accumulate in a localized cavity. Typically, drains are used in an abscess cavity, to treat pneumothorax, or evacuation of blood, serum or lymph from a wound. Drains also remove pus or transudate or alternately to irrigate cavities. The process of drainage eliminates the dead space in a cavity. Herein and throughout this disclosure the cavity will be referred to as the wound or surgical site no matter what the reason for the cavity to be drained. Drainage systems are closed if they capture the fluids with tubing coupled to a closed container or canister and are open if fluid is accumulated in gauze or corrugated rubber sheet. Canisters and collapsible vessels use vacuum or the restoration force of the collapsed vessel to provide respectively, active high or low drainage pressure. Completely passive drains operate on the pressure differential between the inside and outside of the body.
Porex of Newnan, Ga. makes bulb drains and so does Chimed (Via dell'Artigianato, 49 57121 Livorno, Italy that also makes bellows drains; all those are relatively low pressure drains. Chimed also sells a Drenomax high vacuum canister to actively apply vacuum to the drain tubing. Alternatively there is a Drenomax passive drain bag that merely uses pressure differential to accumulate the fluid flow from the drain tube without any vacuum. Chimed also sells Drenomed S-line and R-line drains that are extruded medical grade silicone structure with longitudinal ducts open to the body cavity for passing fluid and the open channels are for resisting clogging. Those semi-rigid structures resist kinking and tissue in-growth. Ethicon a part of Johnson & Johnson sells Blake round and flat extruded structures that are similar in construction and purpose to the R-line and S-line drains. These drains are essentially open ducts within the body cavity and enter a hub connected to the collection vessel or container so that the fluid may be captured as it leaves the body. Degania Silicone of Cumberland, R.I. makes canisters, perforated tubes and bulbs. Jackson-Pratt makes a drainage bulb with a tube to place into the surgical area; again the collapsed bulb draws the fluid from the surgical area and can be emptied and reused. A drain for a wound or surgical site is needed that is less intrusive, is removed easily, is more effective, remains flexible and is capable of guiding fluid flow from the body without kinking or creasing so that healing accelerates and trauma is minimized. Typical tubular drains are placed in the patient after surgery to allow fluids that accumulate in the wound or surgical site after surgery to pass from within in the body to a capture container for analysis and then disposal. Drainage is essential to removing detritus caused by and generated during surgery and healing. The quicker drainage takes place, the faster healing proceeds and the patient recovers.
The human body responds to surgical intrusion initiating healing with white cells, swelling and bleeding. That healing response results in an automatic bodily clean up of the wound or surgical site. Healthy patients heal quickly as a result of the automatic healing response and good drainage accelerates that process. Removal of detritus promotes prompt recovery. Closure of the surgery typically includes a drain tube to allow the results of clean up to leave the body.
Recent U.S. Pat. No. 6,605,068 includes a gravity drainage cord formed by braiding a plurality of strands of silk of the type used for surgical sutures, and fitted or assembled loosely, in the median region, in a tubular sheath made of a material such as silicone. The outer silicone tube facilitates sliding of the assembly with respect to tissue, increases biocompatibility and allows optional coupling to mechanical aspiration units. Capillary action is said to be the mechanism of drainage. The protrusion of the cord into the wound allows small movement and if more than one cord is used some distributing and spreading are taught to increase drainage. Inside the cavity to be drained the tube may have radial holes to facilitate drainage. No use of the cords without the tube is acceptable and no mechanism other than capillary action is disclosed. The disclosure of U.S. Pat. No. 6,605,068 is incorporated by reference and made a part of this background.
The therapeutic effect of promoting drainage from wound cavities is known and has been the subject of devices to promote drainage have come in many forms, but may be classified generally in three groups. The first general group, have a hollow structure, such as a tube, which is placed in the wound to allow the removal of wound discharge by, e.g., capillary action and/or siphoning and/or gravity. A number of these “tube” type drains have also been used in conjunction with vacuum producing apparatus to actively assist drainage. Advantages shared by tube-type surgical drains are ease of insertion into a wound cavity and the volume of discharge does not generally affect their drainage function. As they provide constant drainage, the need to replace them is reduced. There are a number of disadvantages of tubular surgical drains including the difficulties of avoiding infection and promoting healing inherent in a device inserted in a wound cavity. Tubular surgical drains tend to be prone to blockage and other forms of obstruction, e.g., when the tube opening contacts body tissue the passage of discharge may be plugged or obstructed.
The second general group, of surgical drain devices, include those made of various forms of fibers and fabrics having absorptive properties, that are placed in a wound cavity to allow removal of wound discharges, e.g., by absorption. Advantages shared by these “fabric” type surgical drains are that they can be sized relatively easily and manipulated regardless of the size of the wound cavity and they are less prone to blockage or obstruction than tube-type drains. As with tube-type drains, fabric drains suffer from a number of disadvantages, such as susceptibility to sloughing or fragmentation, which may promote irritation and associated infection, and their drainage capacity maybe limited to the fluid retention capacity of the fabric, i.e., the drainage is not continuous. Using hydrophilic fibers, e.g., cellulose derived and yarns may aggravate flow problems, due to their water binding properties. A consequence of the drainage capacity limitation is that fabric-type surgical drains must ordinarily be replaced on relatively short intervals.
U.S. Pat. No. 6,135,116 has an active drainage system with positive and negative pressure applied to a wound dressing applied to a foot ulcer by a foot wrap. The use of vacuum applied to gauze is thus taught. U.S. Pat. No. 6,135,116 is incorporated by reference and made a part of this background.
Conventional fabric-type drain materials are often so loosely woven that they fragment which increases the risk of infection. Moreover, natural fibers like cotton, and other cellulose, are themselves prone to sloughing or fragmentation that also increase the risk of infection. In addition, depending on the fibers selected, known fabric-type surgical drains may decompose over time, again necessitating more frequent replacement, and irritating of the wound cavity. Another limitation of known fabric-type surgical drains is that, once positioned, they may be difficult to relocate or retrieve.
The third general group, of surgical drain devices, is a hybrid of the described tubular and fabric drains including both a hollow structure and absorptive fibers. In these combination surgical drains, a fabric is usually either wrapped around or arranged within a hollow structure to form a composite to insert into a wound. Combination drains enjoy some of the advantageous properties of both tube and fabric-type drains. While this type of drain has the advantage of ease of manipulation and may have better drainage characteristics than the other general types of surgical drains, it may also suffer from their disadvantages. An example of a combination-type drain routinely used in surgical procedures, is made from gauze, e.g., a loosely woven cotton fabric, which may be layered and cut to size and then placed in either surgical sheathing or a tubular part cut from a rubber glove prior to insertion into a wound cavity. The surgical sheathing or rubber glove part is used to help prevent loose fragments or threads of the gauze from entering the wound cavity. Gauze is prone to fragmenting leaving many loose threads when it is cut and additional parts of the fabric may fall away under minimal pressure in the form of lint. The use of the sheath or glove to contain lint is not completely effective or convenient for use in an operating room setting. Furthermore, drainage with this type of surgical drain may be limited to the fluid retention capacity of the fabric and evaporation. Typical of this is FIG. 9 in U.S. Pat. No. 5,358,492 with absorbent filler cord within the surrounding woven warps and wefts forming tube like channels. U.S. Pat. No. 5,358,492 is incorporated by reference and made a part of this background.
Other known surgical drains, include ‘cigarette drains’, made by surrounding a strip of gauze with a protective covering of rubber, gutta-percha, or the like; and drains formed by pushing a single layer of gauze into a wound cavity, the layer of gauze being packed with several thick wicks of gauze as it is pushed into the cavity. As with other known surgical drains, these drains have lint and their drainage capacity may be limited to the fluid retention capacity of the fabric.
Often a vacuum may be applied to the external end of the tubular drain to aid in removal of detritus. The vacuum will tend to overcome clogging of the fluids drawn through the drainage tube. Specifically, the drainage detritus include fluids with tissue, blood and other cellular matter. Thus the drainage fluids are often quite thick or viscous and adhering to the inside of the tubular drain restricting flow or even coagulating forming a restriction therein notwithstanding vacuum application.
Another problem encountered with the using of tubular drains is that drainage is localized about the internal end of the tube particularly when vacuum is applied externally. Localization of drainage is not effective to remove the detritus and accelerate healing of the wound or surgical site. Drainage is drawn primarily from the area adjacent to the internal end; thus, fluid is drawn mostly there from and not through out the wound or surgical site. Moreover, the vacuum applied to the drain tube can draw the adjacent internal tissue into the internal end resulting in restriction of flow and perhaps collapse of the tubular passageway stopping drainage and requiring withdrawal and removal and replacement of the drain tube. Additional trauma to the wound or surgical opening and interference with the healing process are detrimental and undesired consequences. To prevent collapse of the tubular passageway drain tubes are made with a thick wall to resist the high vacuum necessary to draw the detritus out of the wound or surgical site. Increased vacuum promotes restriction caused by internal tissue drawn into the end of the drain tube.
Yet another difficulty with tubular drains is their relatively rigid circular cross section. In particular, the incision made through the skin to enter the body is often linear or a puncture and thus not circular. When the wound or surgical opening through the skin is cut by a scalpel, tom by puncture or is an injury, it has a rough edge. Typically, the tubular drain placed in a surgical opening is sutured to the patients skin to maintain its position. If suturing is performed to secure the tube, it pulls and is uncomfortable during drainage and removable.
A better drain is needed to anatomically fit percutaneously into or through the wound or surgical opening and draw fluid from inside the wound or surgical site. Guiding fluid from inside the wound or surgical site and resisting clogging, impediment and localization would be welcome during external removal of accumulated detritus. An improved drainage apparatus and methods of use and manufacture that can take the place of a tubular drain to accelerate wound or surgical site clean up and healing would be of value and aid healing.